The present invention generally relates a combustor liner in a turbine engine, and, more specifically, to a multi-axial pivoting combustor liner that minimizes thermal interference during engine operation. A gas turbine engine includes a compressor that provides pressurized air to a combustor wherein the air is mixed with fuel and burned for generating hot combustion gases. These gases flow downstream to one or more turbines that extract energy therefrom to power the compressor and provide useful work such as powering an aircraft in flight. Combustors used in aircraft engines typically include a combustor liner to protect surrounding engine structure from the intense heat generated by the combustion process.
A conventional can combustor liner has a cylindrical shape with one open end. A thin sheet metal material, capable of withstanding high temperature conditions, is usually used to fabricate the body through a forming process. The liner is often supported on one end or suspended by a few points. The conventional liner assembly and fabrication technique is adequate only for low cycle and low performance engines.
U.S. Pat. No. 3,911,672 discloses a combustor having a ceramic liner. Referring to FIGS. 1 and 2 of the patent, an abutment 22 includes a flange 24 engaging the liner surface of a dome 6 around an opening 7. A slightly yieldable or resilient gasket 25 is disposed between flange 24 and the ceramic liner. This conventional system relies on bolts and screws to make the assembly. The combustor described in the patent does not, however, have multi-axial pivoting capabilities.
U.S. Pat. No. 4,446,693 discloses a cooled wall structure for a gas turbine engine in which the wall is capable of providing a relative movement to cope with the thermal strains experienced by the combustion process. Referring to FIGS. 3, 7 and 8, the wall structure has an inner wall 20 and an outer wall 18. Attachment is provided by a central pin 28a passing through an opening 30 in the outer wall. Central pin 28a is secured to outer wall 18 by welding. Outer pins 28b, on each side of central pin 28a, pass through an opening 32, and a collar 34 is attached to each wall outer pin 28b. Thus, the downstream end of each wall element is securely attached to the outer wall by central pin 28a and is located on the outer wall by outer pins 28b so that the wall element moves to a limited extent with respect to central pin 28a. The wall of this patent is a cooled slidable wall that does not have multi-axial pivoting capabilities, and, more to the point, is not capable of any pivoting motion.
As can be seen, there is a need for an improved combustor liner for gas turbine engines. Such an improved combustor liner must have the ability to control small amounts of air leakage, provide easy assembly, have no flow path steps, and tolerate thermal and mechanical stresses while minimizing thermal wear and fretting for the life of the liner.